Reply to discussion of Jamaican cenozoic ichnology: review and prospectus: (v. 50, p. 364–382)

Mitchell and Ramsook comment on the lithostratigraphic assignment of Jamaican Cenozoic ichnofossils discussed in Donovan et al. They argue that the Paleogene Richmond Formation should be subdivided to produce a ‘Moore Town formation’ in eastern Jamaica, but the latter remains undefined as a lithostratigraphic unit and no new lithostratigraphic evidence is produced to support their supposition. Further, their use of a flawed table of trace fossil distributions does not support their thesis. The distribution of trace fossils in the White Limestone Group presented by Donovan et al. follows the lithostratigraphic scheme that was current at the time that the research was originally undertaken in the early 2000s. Yet, whatever lithostratigraphic scheme is utilised for the island, it is apparent that the more accurate data is provided by the biostratigraphy of the larger benthic foraminifers. Copyright © 2015 John Wiley & Sons, Ltd.     

Where are all the crinoids? An enigma of the Lower Carboniferous (Mississippian) White Peak of midland England

A glut of fossil crinoids does not lead to a succession being recognised as rich in crinoids. Crinoid palaeontology relies on cups, crowns and complete specimens, not fragments. The Carboniferous Limestone of the White Peak is rich in crinoid fragments, but depauperate in named crinoids. Something needs to be done.     

Monodomain behaviour in multiphase oxidized titanomagnetite

Large grains, of the order of tens of microns in size, of synthetic titanomagnetite have been oxidized to produce an intergrowth of phases, essentially similar to that produced by the natural process of deuteric oxidation. The scale of the intergrowth is at the limit of the optical range but the electron microscope reveals the characteristic lamella microstructure. The magnetic hysteresis properties of the most highly oxidized material, having probably about 10% of residual spinel phase, are typical of dispersed monodomain magnetite rods. The investigation therefore supports the model in which it is proposed that titanomagnetite grains in a slowly cooled basalt may carry a highly stable component of natural remanent magnetization.     

Trace element distribution and oil yield data from the parachute creek member of the green river formation,colorado

The determination of trace element concentrations in oil shale before mining and retorting is required for proper solid-waste management planning. Using routine Fischer assay oil yield data collected during resource characterization as indicators of potential trace element concentrations could lead to a standard method of identifying strata containing high trace element levels. In order to determine a correlation between trace element concentrations and oil yield, shale samples were selected from four statigraphic zones of the Parachute Creek Member of the Green River Formation for analysis. All samples were analyzed for total elemental concentrations, mineralogy, and Fischer assay oil yield. The results of these analyses demonstrated that the Mahogany zone shales contain significantly greater trace element concentrations (antimony, arsenic, cadmium, chromium, copper, lead, lithium, mercury, molybdenum, nickel, selenium, silver, and vanadium) than the other three shale zones. These high trace element concentrations have been identified within well-defined interbedded tuff deposits in the Mahogany zone. In addition, all trace elements evaluated, except boron, show either increasing or decreasing concentrations as oil yield increases within all oil shale zones. With an increased number of analyses of existing oil shale cores, oil yield data will be correlated to specific stratigraphic units containing high trace element concentrations.